T-Frac System Run in System

ABSTRACT

A central slant hub tool is provided which is capable of receiving tubing or a tool such as a drill from the surface and directing the tube or tool laterally outward using an exit line slant surface or directing the tube or tool downward to an area below the tool. In this way, the tool acts as a hub to communicate with both lateral branches and lower zones of the main casing. Fracture window tools may be installed in the lateral and lower branches to selectively open the bores for drilling, testing and/or production or may be sealed by a bridge plug or the like when not in use.

This application claims the benefit of U.S. Provisional Application 61/286,892, filed Dec. 16, 2009, T-Frac System Run in System, which is incorporated herein by reference.

At least one aspect of the present application relates to a system and method for running in and utilizing a selectively openable window in a down hole well having side extending (“lateral”) branches.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present application relates to a method of testing zones in a well and a system therefor.

2. Description of the Prior Art

Oil and natural gas wells are drilled deep into the earth. A central bore (“main drill hole”) is made with into the earth and stabilized with a steel pipe (“casing”) inserted into the hole to maintain the integrity of the bored hole and to separate various zones of the well found at different depths in the well. Different production zones may be operated on by drilling out sideways through openings (“windows”) created in or existing in the casing at various depths to communicate with these zones. Over time, these zones may be tapped out, may collapse or may continue to be productive. Because of the depths involved and the inaccessibility of these production zones to workers, it may be difficult to ascertain the condition of various zones. Additionally, it may be very expensive to lower hundreds or thousands of feet of a drill string (i.e., down hole work tools) into a well to check on a particular zone, remove all of the tools and reinsert to check a different zone. Therefore, there exists a need to be able to test various fracture zones and operate on various lateral wells without having to raise and lower all of the equipment. The present invention describes in at least one embodiment, a method of using a slant hub tool that performs several functions including directing equipment to lateral openings and directing drilling equipment.

None of the prior inventions and patents to date, taken either singly or in combination, is seen to describe the instant invention as claimed.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of a preferred embodiment of the invention to provide a hub tool that can be raised or lowered to address various fracture zones.

It is another object of the invention to provide hub test tool that allows equipment to selectively be lowered through the hub tool or sent laterally outward.

It is a further object of the invention to provide a system of packers and hub tools that allows a number of zones to selectively be operated upon or closed in favor of another zone.

Still another object of the invention is to provide a hub test tool that can be locked into proper orientation to direct drilling equipment to the proper direction.

It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.

These and other objects of the present invention will be readily apparent upon review of the following detailed description of the invention and the accompanying drawings. These objects of the present invention are not exhaustive and are not to be construed as limiting the scope of the claimed invention. Further, it must be understood that no one embodiment of the present invention need include all of the aforementioned objects of the present invention. Rather, a given embodiment may include one or none of the aforementioned objects. Accordingly, these objects are not to be used to limit the scope of the claims of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is diagrammatic cross-sectional view of a hub tool according to the present invention

FIG. 2A is diagrammatic cross-sectional view of a reconnect tool for the hub tool.

FIG. 2B is a diagrammatic view of a re-entry tool for use with the hub tool.

FIG. 2C is a diagrammatic view of the slant line of the hub tool.

FIG. 2D is a diagrammatic top and side views of the slant line of the hub tool.

FIG. 2E is a diagrammatic front view of the hub tool slant line.

FIG. 3 shows the t-frac system being run in on a casing.

FIG. 4 shows the t-frac system packers set and a retrievable bridge plug in place.

FIG. 5A shows the t-frac system being released.

FIG. 5B shows a J tool for use with the reconnect tool.

FIG. 6A shows a UBHO tool being run in to line up the window of the hub tool slant is line.

FIG. 6B shows the J tool in the tension position.

FIG. 7 shows the tool being detached from the running tool and lowered to the lower packer.

FIG. 8 shows the tool being raised to the upper packer.

FIG. 9 shows the upper sub being released from the tool.

FIG. 10 shows the top sub being released from the tool.

FIG. 11 shows the system ready for drilling.

FIG. 12 shows drilling equipment directed through the hub tool to a lateral zone.

FIG. 13 shows a lateral bore being drilled.

FIG. 14 shows a second t-frac system being set in the lateral bore.

FIG. 15 shows the lower bridge plug being removed.

FIG. 16 shows the lower t-frac system ready for production or working.

FIG. 17 shows a bridge plug being reintroduced to the lower t-frac system.

FIG. 18 shows the casing being removed from the lower t-frac.

FIG. 19 shows casing being run in to work the later zone.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

At least one aspect of the present invention is to a method and apparatus for drilling and completing a down hole well having lateral branches.

Natural gas deposits are commonly exploited by separating a well into separate zones and using packers between the zones so that a particular zone may be individually worked. It is also often necessary or desirable as part of the zone treatment of the wells to drill laterally outward from a main vertical casing to enhance or cause a zone to communicate with the vertical casing.

FIG. 1 shows a central slant hub tool 110, which is capable of receiving tubing or a tool such as a drill from the surface and directing the tube or tool laterally outward using an exit line slant surface 112 or directing the tube or tool downward to an area below the tool. In this way, the tool acts as a hub to communicate with both lateral branches and lower zones of the main casing. The slant hub tool also has a number of connectors and is shear pins that will be explained further hereunder.

In practice, the slant hub tool may be connected to a zone test window system 113, which is further detailed in co-pending U.S. provisional application 61/257,878, filed Nov. 4, 2009, which is incorporated herein by reference. The combined slant hub tool and test window system according to a preferred embodiment of the invention is connected to a run in tool, such as a 4½ inch casing 114 (FIG. 3). The casing 114 may be attached with a safety break or other device for separating the components as necessary. Once the depth of the slant hub tool has reached the desired depth, packers 116, 118 on the slant hub tool may be expanded to lock the slant hub tool 110 in place, but are preferably left uninflated for the reasons discussed below. One or more centralizing tools 120 may be provided having a slightly larger diameter than the uninflated packer to prevent the packer from chafing on the casing of the well as the tool is lowered and maintained in place.

It should be noted that the casing 114 is shown in front of the slant hub tool in the drawings to show the details of the casing and connected components, but in actuality is received within the slant hub tool. The outer diameter of the casing 114 is small enough that the casing will pass through the exit slant tool 112 via opening 122 (FIG. 1) in the slant tool, allowing the casing to by-pass the lateral window 123 and pass through the exit slant tool 112 to the lower end of the slant hub tool 110. Preferably the slanted face is between 15 and 75 degrees to the axis of the slant tool to allow the casing to smooth transition from the bore to the lateral direction, but may be more or less than this amount depending on the length of the transition and diameter of the tools. At a lower surface of the casing are threads 124 that mate with the threads 126 on a re-entry tool near the bottom of the slant hub tool. The re-entry tool may have a bevel or neck 125 for aiding in guiding the casing threads into proper alignment with the re-entry tool threads. The casing includes an extended length of tubing or casing at an upper end so that the slant hub tool may be lowered in a well outer casing 127 to the desired depth and locked in place.

Once the slant hub tool is in place, the zone test window system (“window system”) packers 130 may be set to lock the window system in place (FIG. 4). A bridge plug 132 may be installed (“run in”) with an appropriate tool in the window system tubing to prevent communication of fluid between the slant hub tool 110 and the window system 113 or vice versa. In this way the zone below the slant hub tool is secured by the packers and the bridge plug to isolate the slant hub tool.

The run in casing 114 may then be released from the slant hub tool 110 by releasing threads 124 on the run in casing 114 from the threads 126 on the slant hub tool 110. The run in casing is, however, not free to lift completely from the slant hub tool, but instead has a orientation knob 130 which will run up to a J tool 131 (see FIG. 5B) inside the re-connect tool 133 to properly orient the slant hub tool relative to the run in casing 122. This will also lock the tools together so that tension or compressive forces on the run in casing will be transferred onto the slant hub tool through the J tool to complete various operations as will be explained further hereinunder. More importantly though, the slant hub tool must be properly oriented so that the window 123 of the tool is facing in the direction that drilling is to be performed.

A lower edge of the slant hub tool has a spline (“castle lock”), between the lower portion of the slant hub tool and the lateral window exit tool. This allows for reorientation of the window without having to move all portions of the tool, which prevents the unintentional release of the threaded tools when orienting the window. By running the run in casing knob to the tension position (FIG. 6B), lifting on the run in casing will apply tension to the slant hub tool. The casing will be allowed to lift in the tension channel 139 of the J tool without also lifting the slant hub tool. Applying a large tension such as 5000 lbs will shear pins locking the spline tool in place. By disengaging teeth of the spline tool through this lifting, the slant hub tool can be rotated to orient the window 123 in the proper direction. A swivel guide 135 with its flange 137 prevents the tool from being raised too far and separating the parts of the slant hub tool, while allowing free rotation of the tool. The compression channel 141 allows compressive forces on the casing to press the spline tool back in place.

If necessary, a tool such as a Universal Bore Hole Orientation (“UBHO”) sub 134 (FIG. 6) can be used to aid in orientation. A UBHO sub, such as that described in U.S. Pat. No. 3,633,280, issued Jan. 11, 1972, which is incorporated herein by reference, can be used to determine the actual orientation of the opening 123 and to orient the window as needed.

Once the orientation of the window has been set, the tension can be released from the slant hub tool to lock the spline back in place and fix the orientation of the window 123 in the desired direction. In this way, the window system below the slant hub tool is unaffected during the reorientation of the slant hub tool.

With the window oriented in the proper direction, the slant hub tool can now be set in place through its packers 116,118 (FIGS. 7-8). While there are a number of methods that can be used to set a packer, the packers 116,118 are preferably set by detaching the run in casing and straddling the lower packer to pressurize the packer, for example at 2000 psi, and then repeating the process on the upper packer. Cup type packers 144 can be directed above and below the packer to be inflated to generate the required pressure. A ball 146 dropped into the casing may be used to help set the cup packers and to direct fluid to the packers through a lateral opening 148 instead of passing straight through the casing. At this point, the slant hub tool 110 and associated window 123 will be locked in place. The flow may be reversed through the casing at this point to retrieve the packer setting ball in the casing so that fluid will again flow through the casing unobstructed again.

With the slant hub tool locked in place, a bridge plug 132 (FIG. 8) can be tripped in, for example, by wireline and set in place to protect the area below the window during drilling and production. This bridge plug may be in addition to or in place of a previous bridge plug 132.

The run in casing may now be removed. A right hand rotation will unthread releasing tool 150 (FIGS. 9 and 10) from the slant hub tool 110. The run in casing and releasing tool can thus be tripped out of the hole along with any other setting equipment. The system is now ready for drilling (FIG. 11).

As shown in FIG. 12, lateral drilling equipment 154 may be introduced into the casing to drill an upper lateral well. Because the drilling equipment (or a collar therefor) 155 is larger than the pass through opening 122, the equipment will be directed along the lateral slanted face of exit slant 112 through window 123. The drilling equipment can thus be directed outwardly to drill a lateral wellbore in the desired area 157 adjacent window 123 (FIG. 13).

Once the wellbore is drilled to a sufficient length, a second t-frac (“window”) system 158 (FIG. 14) can be run into the new lateral wellbore on a run in casing and packed off. A wireline bridge plug 132 (FIG. 15) can be installed in the opening to the new window system 158 to protect the window system during production or further drilling prior to removing the run in casing. In this way multiple zones can be made ready for access, testing or production.

As shown in Stage 15, the run in casing used to run in the new window system 158 can be removed (e.g., unthreaded or disconnected) from connection with the new window system raised and then lowered into connection with the lower re-entry guide. Because the run in casing 114 is not attached to the new window system 158 as it is lowered through the slant hub tool 110, it will have an outer diameter smaller than the pass through opening 122 and can pass through the slant hub tool into connection with the re-entry tool. Threads 124 of the casing 114 can then re-thread to the re-entry tool threads 126. (See FIG. 5A)

The retrievable bridge plug 132 (FIG. 15) can now be pulled. (FIG. 15) to communicate with the lower window tool 130. The lower window system is now ready for production, testing or other operation such as fracturing (“frac”), the processing of forcing specially blended fluids or other materials into a hole to increase the size (“crack open”) of fractures in a wellbore to enhance potential flow rates through the resulting passages. The use of strategically placed bridge plugs ensures that the fluids are directed only to the intended areas during this fracturing. Since the casing is connected (“threaded”) to the re-entry tool, it may not be necessary to plug lateral bores above the re-entry tool, since the threads between the casing and the re-entry tool will act to prevent fluid from flowing to higher zones.

As shown in FIGS. 17 & 18, when fracturing is completed on the lower zone, the lower zone may be bridge plugged, and the casing may be disconnected (“unthreaded”) from the re-entry tool and raised until connected to the reconnect tool 133. With the lower window system plugged and the casing above the lateral bore, the lateral bore can now be fractured. Any bridge plug in the upper lateral should be removed prior to fracturing.

Once the upper lateral has been fractured, coil tubing (i.e., a length of spooled piping) can be used with a retrieval tool to retrieve the bridge plug on the lower window tool. At this point, with the bridge plug and retrieval tool tripped out of the well, the well is ready for production and has multiple zones for possible re-entry. The use of multiple windows could also be used to increase the number of production zones, with the sizing of the pass-through ports used to determine the routing of drills and other tools through the system to address the desired area.

While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, uses and/or adaptations of the invention following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains and as maybe applied to the central features hereinbefore set forth, and fall within the scope of the invention and the limits of the appended claims. It is therefore to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims. 

1. A down hole hub tool for directing down hole tools, comprising: the hub tool comprising a substantially cylindrical body having an axial bore extending between a top and bottom of said body, said cylindrical body further having a lateral opening on an outer circumference of the body located between the top and bottom of said body, wherein said lateral opening is in communication with said lateral bore; said hub tool having an inner surface within said axial bore slanted 15 to 75 degrees from the axis of the hub tool and being adjacent said lateral opening, said slanted surface defining an axial opening within said face coaxial with said axial bore, wherein said axial opening has a radius smaller than said the radius of said axial bore but at least half of the diameter of the axial bore.
 2. A method of operating a downhole well having a vertical well casing, comprising: providing a hub tool within said well casing, said hub tool comprising a substantially cylindrical body having an axial bore extending between a top and bottom of said body, said cylindrical body further having a lateral opening on an outer circumference of the body located between the top and bottom of said body, wherein said lateral opening is in communication with said lateral bore; providing said hub tool with an inner surface within said axial bore slanted 15 to 75 degrees from the axis of the hub tool adjacent said lateral opening, said slanted surface defining an axial opening within said face coaxial with said axial bore, wherein said axial opening has a radius smaller than said the radius of said axial bore; providing a down hole tool having a radius smaller than said the radius of said axial bore and larger than the radius of said inner surface axial opening; lowering said down hole tool through said hub tool along said slanted surface and laterally outward through said later opening into the ground laterally surrounding said well casing.
 3. A method of operating a downhole well according to claim 2, wherein said down hole tool is a drill.
 4. A method of operating a downhole well according to claim 2, further comprising: providing a packer tool above and below said hub tool to selectively secure said hub tool within said well casing or allowing the hub tool to move within said well casing.
 5. A method of operating a downhole well according to claim 2, further comprising: lowering a first run in casing into said well bore and through said inner surface axial opening of said hub tool to communicate with an area of the ground below said well casing.
 6. A method of operating a downhole well according to claim 5, further comprising: providing an upper reconnect tool connected to said hub tool; said upper connect tool having a J slot tool for selectively providing tension or compression to said hub tool as said run in casing is lifted up or down; providing a castle lock tool connected to said hub tool and having upper teeth and lower teeth interlocked for selectively rotating said lateral opening in a desired location or maintaining the later opening in a selected orientation; lifting said first run in casing to cause a knob on said casing to move said J tool into said tension position to release the upper teeth from the lower teeth on said castle lock; rotating the lateral opening to the desired orientation; setting the run in casing down to interlock the upper and lower teeth of the castle lock to maintain the lateral opening in the desired location.
 7. A method of operating a downhole well according to claim 6, further comprising: using an OBHO tool to orient the lateral window in a predetermined direction.
 8. A method of operating a downhole well according to claim 5, further comprising: running in a t-frac window system on the run in casing through the hub tool axial opening to a location below the hub tool.
 9. A method of operating a downhole well according to claim 8, further comprising: running in bridge plug tool to a location above the t-frac window system to terminate fluid communication along the well casing between the t-frac window system and the hub tool.
 10. A method of operating a downhole well according to claim 5, further comprising: removing the run in casing from the well casing; inserting a second run in casing having a radius larger than the axial opening to cause the second run in casing to move along the slanted inner surface and out the later window; installing a second t-frac window system in a later bore laterally outward from the well casing.
 11. A method of operating a downhole well according to claim 5, further comprising: running in bridge plug tool to a location upstream from the second t-frac window system to terminate fluid communication between the second t-frac window system and the hub tool.
 12. A method of operating a downhole well according to claim 5, further comprising removing the second run in casing from the well casing. 